Münster 1997 – wissenschaftliches Programm

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O: Oberflächenphysik

O 23: Diffusion/Wachstum auf Metallen

O 23.6: Vortrag

Mittwoch, 19. März 1997, 17:15–17:30, S 10

Self-organized growth of periodic island arrays on > single crystal surfaces — •M. Giovannini, K. Bromann, H. Brune, and K. Kern — Institut de Physique Expérimentale, EPF-Lausanne, >CH-1015 Lausanne

> >We studied the possibility of growing a regular array of almost mono-dispersed >islands on a single crystal surface. The method takes advantage of the fact that >dislocations may represent very effective repulsive barriers for diffusing >adatoms. Therefore, a periodic network of dislocations can be exploited to >confine adatoms and to nucleate equidistant islands with the periodicity of >the superstructure. As a consequence of the regular island spacing also their >size distribution is significantly narrowed with respect to isotropic >substrates. We will illustrate this effect for Ag nucleation on the trigonal >dislocation network formed by the second Ag monolayer on Pt(111). At a well >defined deposition temperature there is exactly one island that forms per >superstructure unit cell, below this temperature there are more, and above >adatoms can cross dislocations and hence form less islands. The strong >repulsion at dislocations is reflected in a significantly increased slope >in the Arrhenius plot of the island density. The nature of the strong >repulsion at dislocations is discussed. > > >